<!DOCTYPE html>
<html>
<head>
  <script src="http://code.jquery.com/jquery-latest.js"></script>
</head>
<body>
  <table>

    <tr><td>First Row</td></tr>
    <tr><td>Middle Row</td></tr>
    <tr><td>Last Row</td></tr>

  </table>
<script>$("tr:last").css({backgroundColor: 'yellow', fontWeight: 'bolder'});</script>

</body>
</html>